as a matter of fact, that's almost the same concept as the one being seriously considered for interstellar solar sails, except instead of a nuclear powered 'beam', it's a laser placed very close to the sun in order to capture the enormous amount of solar power necessary to propell a massive ship.

So how much energy can be transmitted? What sort of losses, and more importantly how easy and how far?

i don't know the exact stuff of course, i don't think anyone does because it's never been tried, but i think the answers are as follows: as much as you can make, not much loss, <fairly> easily, and potentially infinite.

If that's true, it's incredible that we haven't tried to harness this more fully. A nice big satellite sucking up solar energy with a nice fat collector, beaming power other satellites that need lots of power but don't have solar arrays big enough to satisfy those power requirements.

A smaller communications satellite could pump the signals out at a higher wattage, and so replacing bigger older satellites. And the smaller they are, the cheaper they are to get into their intended orbits. Nice!

Hey look at the ISS. How much more could be done with an extra megawatt or two of power on tap. Useful things could be done. There would be less need for the solar panels, and so the station could expand easier too.

Yep, the problems are also quite big, but once solved, this could well be a useful manner to power some orbital facilities, and/or interplanetary vehicles. The further out you go, the less useful solar energy is available. If we can beam it to them....

Its very scary firing high energy beams around in space... if your aim drifts just a little away from the collector, you fry whtever is holding the collector...

This means you interplantary probe of craft could get fried by a minor gyro instability by a satellite in earth orbit. Not cool.

To be of real benefit to earth an orbital solar array would have to be huge. Really really huge, like see it in the daytime huge. However a simple environmental lawsuit could shut it down for a while stopping most people from investing in such and idea even after launch costs come down 100-fold.

But it is an interesting thread to follow. The big big colonies are refered to as O'Neil colonies after their proponent.

Its very scary firing high energy beams around in space... if your aim drifts just a little away from the collector, you fry whtever is holding the collector...

This means you interplantary probe of craft could get fried by a minor gyro instability by a satellite in earth orbit. Not cool.

To be of real benefit to earth an orbital solar array would have to be huge. Really really huge, like see it in the daytime huge.

a) no, it wouldn't get fried by some minor gyro instability. not only is that rare in well built craft, you'd have some saftey feature that would shut down the beam as soon as the platform started experiencing oscillations.

b) yes i agree that the bigger the collector, the bigger the benefit, so a really good one would be see-it-in-the-daytime big, but it wouldn't be in earth orbit, so you wouldn't. i imagine that the best place to put these collectors is probably somewhere slightly inside venus' orbit, if not closer. the closer you are to the sun, the more energy you capture and the more continuous your flow of power. in fact, i've always thought that one of the ultimate power generating methods for the far, far future would be to enclose a small star in solar collectors built from materials in that system, and use the massive amount of power to manufacture antimatter, which would then be sent out in a fairly steady stream of containers towards a nearby station for harvesting. obviously such a method would be somewhere around 10,000 years away minimum i'd say, though maybe not, but it would be pretty badass if it worked.

. . . of course there's the scenario depicted in the James Bond movie, "Diamonds are Forever." While the scheme shown there couldn't work, one wonders about the possibility of some terrorist getting control of the beam and aiming it where it doesn't belong.

First off: a beam of electromagnetic radiation falls prey to a couple things known as diffraction and diffusion. Space is not a perfect vacuum (far from it, in fact), and thus the light beam will be scattered over time and distance.

Second: think about what you're saying for a moment. You're proposing (let's say) to power a spacecraft to Jupiter by firing a high-power microwave beam at it all the way there. For one thing, this means that you have to track the damned thing all the way there, without losing sight of it for an instant (think about the Moon missions -- how do you beam energy to it while it's on Farside?). Also you've now killed that entire stretch of space -- nothing else with a desire to live can cross that microwave beam. Plus, you have to actually hit the receiving dish -- and once you're a few million kilometers away, that's not an easy task.

The idea of beaming energy from one relatively stationary thing (a collector sattelite) to another (a planet or space station) is workable. However, transferring it from one stationary thing (a collector sattelite) to a moving thing (a spacecraft) is not.

ahh.... but if what you're trying to do is propel a solar sail, then it does work. beaming power to a moving target is not a good idea, but you can eliminate most of the onboard power usage in the first place by using the beam as your engine. and btw, given the size of space, crossing the microwave beam is completely a non-issue.

ahh.... but if what you're trying to do is propel a solar sail, then it does work. beaming power to a moving target is not a good idea, but you can eliminate most of the onboard power usage in the first place by using the beam as your engine. and btw, given the size of space, crossing the microwave beam is completely a non-issue.

True... But a solar sail doesn't need a beam in the first place. The whole point is that the sail is big enough to be propelled by the solar wind alone. A beam would put enough pressure on the sail to tear it to shreds. No argument that space itself is big, but there's only one shortest distance between any two objects. What I'm saying is that you're drastically limiting the number of vehicles that can travel along any given spacelane. Granted that they can travel along other routes, but those routes are quite a bit less efficient and take much more time.

the point of powering the solar sail with a beam isn't that the sun can't push it, just that it can't do so outside of around jupiter's orbit. anything going outside of that needs not only the energy from the sun to get there, but another power source too. if you need to keep accelerating to get there in a decent time (uranus and out i'd assume) then you need the laser to give thrust, and if not then you'd still need it to decelerate into an orbit (have a sail in front of the ship too so to stop just cut the cables linking it and aim the laser to hit it, reflecting the light back onto the sail still attached and slowing the ship).

also realize that for shorter distances, like to mars, a nuclear engine is definitely the best way to get there by far, and maybe even out to jupiter or saturn too (assuming a launch from earth). beyond that it really isn't too effective to use a fueled ship unless it's antimatter or one of those fusion ramjets that are now merely theoretical even discounting the fusion tech needed. at those distances, it's a minor issue of how much space is needed between ships. even if the distance is 10,000 km, which is downright small, but still more than needed if the ships aren't gigantic, the sheer size of space (remember to think 3 dimensions) means that no matter how many you have, it'll only be congested very close to the planets/stations themselves.

i'm surprised at all the nay-saying... nasa is currently doing real life physical experiments with beam-powered flight, both in a fairly mundane way and in a fairly extravagant way

the mundane way: indoors in a hangar using a model airplane, the beam (don't remember what kind of beam) is aimed at the "collector" on the plane (this has been done manually so far) and powers its flight. they are said to be planning outdoors testing in a short while and have plans for automation of the beam targeting as well as using several beams with moderate power levels which are all focused on the same spot to avoid any health hazards. the aim [pun intended] is to use this for energy transfer to mars missions and the like if it proves successfull enough

the extravagant way: the nasa experiments with laser crafts (highpowered laser beams being shot into the underside of a specially shaped "craft" resulting in the superheating of air for propulsion. this stuff was moved outdoors years ago and is a longterm project looking for alternative ground to orbit propulsion afaik

For one thing, this means that you have to track the damned thing all the way there, without losing sight of it for an instant (think about the Moon missions -- how do you beam energy to it while it's on Farside?). Also you've now killed that entire stretch of space -- nothing else with a desire to live can cross that microwave beam. Plus, you have to actually hit the receiving dish -- and once you're a few million kilometers away, that's not an easy task.

I can't agree with this, if anything by the time it's even possible to build such a massive microwave beam emitter I think you'd have to worry more about people intentionally intercepting the beam to steal power than you would have to worry about someone accidentally drifting through such a beam. Besides it'd probably be pretty easy to make any ships higly reflective to the microwave frequencies used for power transmission, which would make them pretty much harmless, at least when compared to all the other radiation concerns of space travel. As far as hitting the dish, the easy thing to do would simply make a larger beam and accept a greater loss of power the further away the ship gets. It still sounds more like an engineering challenge than an impossible task to me though.

I read some time ago that the Japanese are planning an orbital test platform using solar panels that will beam power to earth using microwaves by 2010 or so. I think it's supposed to be a proof of concept type of thing and they want a full scale on operating sometime in the 2020's.